Can't move in the 3D view with mouse
You can try one of the following


View > View selected or . on Numpad
If that doesn't work try Shift + C


It seem that with some blend files "zooming to much" locks the 3D view and you can only rotate the view, not pan or zoom in or out, with other .blend files it is OK... don't know the real source or how to fix the file, anyway if you still want "free zoom, pan and rotate", you can copy the objects that you need to a new .blend.